US6741816B2ExpiredUtilityPatentIndex 83
Tone reproduction curve control method
Est. expiryAug 11, 2021(expired)· nominal 20-yr term from priority
G03G 2215/00054G03G 15/5041G03G 2215/00042G03G 15/00
83
PatentIndex Score
17
Cited by
8
References
25
Claims
Abstract
A toner reproduction curve (TRC) control method is provided. The TRC method for controlling a printer including a color toner density (CTD) sensor includes the steps of (a) measuring a development potential VB, a charging potential VO, an exposure potential VR, and a development current Id and evaluating a development vector VD, which is the difference between the development potential VB and the exposure potential VR, and a backplating vector VBP, which is the difference between the charging potential VO and the exposure potential VR; (b) forming a TRC space using TRC data detected from the CTD sensor; (c) obtaining a TRC characteristic function from the TRC data, the development vector VD=x, the backplating vector VBP=y, and the development current Id=z; (d) forming an RTRC by setting TRC data, whose covariance is smaller than a threshold value among the detected TRC data, as RTRC data; and (e) measuring TRC data, comparing the measured TRC data with the RTRC data to calculate control parameter values, and controlling the printer using the control parameter values. The TRC method does not require other sensors but the CTD sensor. By using internal parameters covering environmental changes, the charging potential of a photosensitive body, a state of a developer, and the efficiency of a charger can be estimated, thereby realizing efficient TRC control.
Claims
exact text as granted — not AI-modifiedWhat is claimed is:
1. A method of controlling a tone reproduction curve (TRC) in a printer including a color toner density (CTD) sensor receiving light reflected from test patches having different densities and photoelectrically converting the received light, the test patches being provided on a photoreceptor belt, the method comprising the steps of:
(a) measuring a development potential V B , a charging potential V O , an exposure potential V R , and a development current Id and evaluating a development vector V D , which is the difference between the development potential V B and the exposure potential V R , and a backplating vector V BP , which is the difference between the charging potential V O and the exposure potential V R ;
(b) forming a TRC space using TRC data detected from the CTD sensor;
(c) obtaining a TRC characteristic function from the TRC data, the development vector V D =x, the backplating vector V BP =y, and the development current Id=z;
(d) forming an RTRC by setting TRC data, whose covariance is smaller than a threshold value among the detected TRC data, as RTRC data; and
(e) measuring TRC data, comparing the measured TRC data with the RTRC data to calculate control parameter values, and controlling the printer using the control parameter values.
2. The method of claim 1 , wherein the step (a) comprises the steps of:
(a-1) measuring the development potential V B , the charging potential V O , the exposure potential V R , and the development current Id; and
(a-2) evaluating the development vector V D and the backplating vector V BP from the measured development potential V B , the charging potential V O and the exposure potential V R , and
the development vector V D and the backplating vector V BP satisfy the following:
V
D
=V
B
−V
R
V BP =V O −V B .
3. The method of claim 2 , wherein the step (b) comprises the steps of:
(b-1) developing a test patch at a high toner area coverage, a test patch at a mid toner area coverage, and a test patch at a low toner area coverage on the photoreceptor belt and detecting a signal T H corresponding to the high toner area coverage, a signal T M corresponding to the mid toner area coverage, and a signal T L corresponding to the low toner area coverage from the CTD sensor receiving infrared rays reflected from the test patches and generating electrical signals; and
(b-2) forming the TRC space using the detected signals T H , T M , and T L .
4. The method of claim 3 , wherein the TRC characteristic function obtained in step (c) is T=KV and satisfies the following: T = [ T L T M T H ] K = [ A L B L C L D L E L F L G L A M B M C M D M E M F M G M A H B H C H D H E H F H G H ] V = [ x 2 y 2 z 2 xy yz zx 1 ] x = V D , y = V BP , z = Id .
5. The method of claim 4 , wherein the step (c) comprises the steps of:
(c-1) obtaining the following non-linear equation satisfying KV−T=0 [ A L A M A H ] x 2 + [ B L B M B H ] y 2 + [ C L C M C H ] z 2 + [ D L D M D H ] xy + [ E L E M E H ] yz + [ F L F M F H ] zx + [ G L - T L G M - T M G H - T H ] = [ 0 0 0 ] ;
(c-2) obtaining a Jacobian matrix J of the non-linear equation as follows J = [ ∂ T L ∂ x ∂ T L ∂ y ∂ T L ∂ z ∂ T M ∂ x ∂ T M ∂ y ∂ T M ∂ z ∂ T H ∂ x ∂ T H ∂ y ∂ T H ∂ z ] = [ J 11 J 12 J 13 J 21 J 22 J 23 J 31 J 32 J 33 ]
in which
J 11 =2 A L x+D L y+F L z, J 12 =D L x +2 B L y+E L z, J 13 =F L x+E L y +2 C L z
J 21 =2 A M x+D M y+F M z, J 22 =D M x +2 B M y+E M z, J 23 =F M x+E M y+ 2 C M z
J 31 =2 A H x+D H y+F H z, J 32 =D H x +2 B H y+E H z, J 33 =F H x+E H y +2 C H z;
(c-3) deducing the values of x, y, and z by combining the following equation obtained from the Jacobian matrix J and the non-linear equation with the detected TRC(T H , T M , T L ) data [ x ( k ) y ( k ) z ( k ) ] = [ x ( k - 1 ) y ( k - 1 ) z ( k - 1 ) ] - ( j ( x ( k - 1 ) , y ( k - 1 ) , z ( k - 1 ) ) ) - 1 ( KV - T ) ( x ( k - 1 ) , y ( k - 1 ) , z ( k - 1 ) ) .
6. The method of claim 5 , wherein the step (d) comprises the steps of:
(d-1) deducing the development vector V D , the backplating vector V BP , and the development current Id by combining the TRC(T H , T M , T L ) data detected in step (b-1) with the TRC characteristic function obtained in step (c);
(d-2) forming the RTRC(T RH , T RM , T RL ) space using TRC(T H , T M , T L ) data, whose covariance is smaller than the threshold value, among the TRC(T H , T M , T L ) data detected in step (b-1); and
(d-3) determining a function having the development current Id as an independent parameter and the development vector V D as a dependent parameter and a function having the development current Id as an independent parameter and the backplating vector V BP as a dependent parameter by curve fitting the development vector V D , the backplating vector V BP , and the development current Id to be suitable to the RTRC(T RH , T RM , T RL ) space formed in step (d-2).
7. The method of claim 6 , wherein in step (d-2), the TRC(T H , T M , T L ) data used for forming the RTRC(T RH , T RM , T RL ) space satisfies the following equation so that the covariance “e” of the TRC(T H , T M , T L ) data used for forming the RTRC(T RH , T RM , T RL ) space among the TRC(T H , T M , T L ) data detected in step (b-1) is smaller than the threshold value:
e =( T L −T RL ) 2 +( T M −T RM ) 2 +( T H −T RH ) 2 .
8. The method of claim 6 , wherein in step (d-3), the function having the development current Id as an independent parameter and the development vector V D as a dependent parameter and the function having the development current Id as an independent parameter and the backplating vector V BP as a dependent parameter satisfy the following equations:
x=C D (1) z 2 +C D (2) Z+C D (3)
y=C B (1) z 2 +C B (2) Z+C B (3).
9. The method of claim 7 , wherein in step (d-3), the function having the development current Id as an independent parameter and the development vector V D as a dependent parameter and the function having the development current Id as an independent parameter and the backplating vector V BP as a dependent parameter satisfy the following equations:
x=C D (1) z 2 +C D (2) Z+C D (3)
y=C B (1) z 2 +C B (2) Z+C B (3).
10. The method of claim 8 , wherein the step (e) comprises the steps of:
(e-1) measuring the TRC(T H , T M , T L ) data in real time;
(e-2) comparing the measured TRC(T H , T M , T L ) data with RTRC(T RH , T RM , T RL ) data;
(e-3) calculating the development vector V D and the backplating vector V BP with respect to the measured development current Id from the TRC characteristic function obtained in seep (c), when the deviation between the measured TRC(T H , T M , T L ) data and the RTRC(T RH , T RM , T RL ) data is greater than a tolerance error;
(e-4) calculating a new development vector V D ′ and a new backplating vector V BP ′ by combining the measured development current Id with the functions of the development vector V D and the backplating vector V BP obtained in step (d-3);
(e-5) calculating a value of a grid potential V G and a value of the development potential V B as the control parameter values using the new development vector V D ′ and the new backplating vector V BP ′ calculated in step (e-4); and
(e-6) controlling the charging potential V O , the exposure potential V R and the development current Id of the printer by applying the value of the grid potential V G and the value of the development potential V B to the printer.
11. The method of claim 9 , wherein the step (e) comprises the steps of:
(e-1) measuring the TRC(T H , T M , T L ) data in real time;
(e-2) comparing the measured TRC(T H , T M , T L ) data with the RTRC(T RH , T RM , T RL ) data;
(e-3) calculating the development vector V D and the backplating vector V BP with respect to the measured development current Id from the TRC characteristic function obtained in step (c), when the deviation between the measured TRC(T H , T M , T L ) data and the RTRC(T RH , T RM , T RL ) data is greater than a tolerance error;
(e-4) calculating a new development vector V D ′ and a new backplating vector V BP ′ by combining the measured development current Id with the functions of the development vector V D and the backplating vector V BP obtained in step (d-3);
(e-5) calculating a value of a grid potential V G and a value of the development potential V B as the control parameter values using the new development vector V D ′ and the new backplating vector V BP ′ calculated in step (e-4); and
(e-6) controlling the charging potential V O , the exposure potential V R and the development current Id of the printer by applying the value of the grid potential V G and the value of the development potential V B to the printer.
12. The method of claim 8 , wherein the step (e) further comprises the step of (e-7) estimating the efficiency of a charger from the development vector V D and the backplating vector V BP which are calculated in step (e-3) and from the development potential V B and a grid potential V G which are measured.
13. The method of claim 9 , wherein the step (e) further comprises the step of (e-7) estimating the efficiency of a charger from the development vector V D and the backplating vector V BP which are calculated in step (e-3) and from the development potential V B and a grid potential V G which are measured.
14. The method of claim 10 , wherein the step (e) further comprises the step of (e-7) estimating the efficiency of a charger from the development vector V D and the backplating vector V BP which are calculated in step (e-3) and from the development potential V B and the grid potential V G which are measured.
15. The method of claim 11 , wherein the step (e) further comprises the step of (e-7) estimating the efficiency of a charger from the development vector V D and the backplating vector V BP which are calculated in step (e-3) and from the development potential V B and the grid potential V G which are measured.
16. The method of claim 12 , wherein the step (e-7) comprises the steps of:
(e-7-1) calculating the charging potential V O and the exposure potential V R from the development vector V D , the backplating vector V BP , the development potential V B , and the grid potential V G according to
V
O
=V
B
+V
BP
V R =V B −V D ; and
(e-7-2) calculating the efficiency “m” of the charger from the charging potential V O and the exposure potential V R according to m = V O V G .
17. The method of claim 13 , wherein the step (e-7) comprises the steps of:
(e-7-1) calculating the charging potential V O and the exposure potential V R from the development vector V D , the backplating vector V BP , the development potential V B , and the grid potential V G according to
V
O
=V
B
+V
BP
V R =V B −V D ; and
(e-7-2) calculating the efficiency “m” of the charger from the charging potential V O and the exposure potential V R according to m = V O V G .
18. The method of claim 14 , wherein the step (e-7) comprises the steps of:
(e-7-1) calculating the charging potential V O and the exposure potential V R from the development vector V D , the backplating vector V BP , the development potential V B , and the grid potential V G according to
V
O
=V
B
+V
BP
V R =V B −V D ; and
(e-7-2) calculating the efficiency “m” of the charger from the charging potential V O and the exposure potential V R according to m = V O V G .
19. The method of claim 15 , wherein the step (e-7) comprises the steps of:
(e-7-1) calculating the charging potential V O and the exposure potential V R from the development vector V D , the backplating vector V BP , the development potential V B , and the grid potential V G according to
V
O
=V
B
+V
BP
V R =V B −V D ; and
(e-7-2) calculating the efficiency “m” of the charger from the charging potential V O and the exposure potential V R according to m = V O V G .
20. The method of claim 10 , wherein the step (e-5) comprises calculating the grid potential V G and the development potential V B as the control parameters from the new development vector V D ′ and the new backplating vector V BP ′, which are calculated in step (c-4), the grid potential V G and the development potential V B satisfying V R = a ( V D ′ + V BP ′ ) 1 - a + b V B = V R + V D ′ V O = V R + V B + V BP ′ V G = ( V B + V BP ′ ) / m .
21. The method of claim 11 , wherein the step (e-5) comprises calculating the grid potential V G and the development potential V B as the control parameters from the new development vector V D ′ and the new backplating vector V BP ′, which are calculated in step (e-4), the grid potential V G and the development potential V B satisfying V R = a ( V D ′ + V BP ′ ) 1 - a + b V B = V R + V D ′ V O = V R + V B + V BP ′ V G = ( V B + V BP ′ ) / m .
22. The method of claim 12 , wherein the step (e-5) comprises calculating the grid potential V G and the development potential V B as the control parameters from the new development vector V D ′ and the new backplating vector V BP ′, which are calculated in step (e-4), the grid potential V G and the development potential V B satisfying V R = a ( V D ′ + V BP ′ ) 1 - a + b V B = V R + V D ′ V O = V R + V B + V BP ′ V G = ( V B + V BP ′ ) / m .
23. The method of claim 13 , wherein the step (e-5) comprises calculating a grid potential V G and a development potential V B as the control parameters from the new development vector V D ′ and the new backplating vector V BP ′, which are calculated in step (e-4), the grid potential V G and the development potential V B satisfying V R = a ( V D ′ + V BP ′ ) 1 - a + b V B = V R + V D ′ V O = V R + V B + V BP ′ V G = ( V B + V BP ′ ) / m .
24. The method of claim 14 , wherein the step (e-5) comprises calculating the grid potential V G and the development potential V B as the control parameters from the new development vector V D ′ and the new backplating vector V BP ′, which are calculated in step (e-4), the grid potential V G and the development potential V B satisfying V R = a ( V D ′ + V BP ′ ) 1 - a + b V B = V R + V D ′ V O = V R + V B + V BP ′ V G = ( V B + V BP ′ ) / m .
25. The method of claim 15 , wherein the step (e-5) comprises calculating the grid potential V G and the development potential V B as the control parameters from the new development vector V D ′ and the new backplating vector V BP ′, which are calculated in step (e-4), the grid potential V G and the development potential V B satisfying V R = a ( V D ′ + V BP ′ ) 1 - a + b V B = V R + V D ′ V O = V R + V B + V BP ′ V G = ( V B + V BP ′ ) / m .Cited by (0)
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